Portable structures such as tents are used in a variety of recreational and sporting activities. For some activities, the most desirable qualities of a tent are roominess and convenience; for other activities, the most desirable qualities are small size and light weight. Tents are typically supported by poles. For example, a tent made of fabric may be erected with poles either inside or outside the tent; and the fabric may connect with the poles at support points. The flexible fabric of the tent sags between the support points, leading to reduced space and impaired headroom in regions of the tent that are distant from support points.